Internal combustion engines, for example, diesel engines, gasoline engines, or natural gas engines employ turbochargers to deliver compressed air for combustion in the engine. A turbocharger compresses air flowing into the engine, helping to force more air into combustion chambers of the engine. The increased supply of air allows for increased fuel combustion in the combustion chambers, resulting in increased power output from the engine.
A typical turbocharger includes a shaft, a turbine wheel connected to one end of the shaft, a compressor wheel connected to the other end of the shaft, and bearings to support the shaft. Separate housings connected to each other enclose the compressor wheel, the turbine wheel, and the bearings. Exhaust from the engine expands over the turbine wheel and rotates the turbine wheel. The turbine wheel in turn rotates the compressor wheel via the shaft. The compressor wheel receives cool air from the ambient and forces compressed air into combustion chambers of the engine.
The compressor stage of a turbocharger often includes a diffuser configured to reduce the speed of the air leaving the compressor wheel. Reducing the air speed causes the air pressure within the compressor stage to increase, which in turn helps to deliver compressed air to the combustion chambers of the engine. The compressor diffuser usually includes vanes extending between the bearing housing and the compressor housing. These vanes direct the spinning air from the compressor impeller into the compressor housing volute. Because the compressor housing, and the compressor diffuser are usually made of different materials, they expand and contract to different extents, making it difficult to attach the compressor diffuser to the compressor housing.
U.S. Pat. No. 6,168,375 of LaRue et al. that issued on Jan. 2, 2001 (“the '375 patent”) discloses a turbocharger having a radial flow compressor with an annular vane diffuser disposed within the compressor housing. The vane diffuser of the '375 patent is positioned within a channel in an axially-facing surface of a compressor housing back plate. The vane diffuser of the '375 patent is also supported at one end by a lip on the back plate and on the other end by a portion of the compressor housing. The '375 patent further discloses that a pin attaches the vane diffuser to the compressor housing back plate. The '375 patent also discloses that the pin prevents the vane diffuser from rotating relative to the back plate.
Although the '375 patent discloses a vane diffuser retained between the compressor housing and a compressor back plate, the disclosed diffuser retention mechanism may still not be optimal. For example, because the diffuser of the '375 patent is radially constrained by the back plate lip and the compressor housing the disclosed diffuser also may not have sufficient room for radial expansion during operation of the turbocharger. As a result, differential expansion between the vane diffuser and the compressor housing and/or the compressor housing back plate may cause damage to the vane diffuser.
The compressor assembly of the present disclosure solves one or more of the problems set forth above and/or other problems of the prior art.